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Bubble-Eye Medaka
AdvancedOryzias latipes
An improved medaka in which the cornea swells to form a bubble over the eye. Discovered in 2008 by a breeder named Kubokouchi, the trait has been recorded appearing by chance in many varieties. The best-known fixed example is Hitomi, a big-eye bubble-eye.
Difficulty
Advanced
Temperature
18〜28℃
Lifespan
2-3 years
Size
Up to about 4cm SL
Diet
Prepared medaka food, green water
About
Bubble-eye is the trait in which the cornea swells so that a bubble forms over the eye. The Medaka Web Encyclopedia lists it as eye trait 20, explained in line with the Japan Medaka Association classification manual. It was discovered in 2008 by Mr Kubokouchi and has been recorded appearing by chance in a variety of lines. The best-known fixed example is Hitomi, a big-eye bubble-eye; in 2009 the trait was discussed alongside miyuki, tainaikou and youkihi transparent-scale as one of the talking points of the medaka world. As a variety, blue big-eye bubble-eye is the established form, created in 2015 by Tsutomu Niitani and certified as Japan Medaka Association new variety No.9. The encyclopedia registers it as type No.0671 under the classification name blue big-eye medaka, with bubble-eye recorded as a common sub-note. Only four varieties carrying the trait are registered in the encyclopedia, far fewer than for the other eye traits.
Source: Wikipedia (CC BY-SA 4.0)
Lifespan of the Bubble-Eye Medaka
The Bubble-Eye Medaka lives 2-3 years.
Size of the Bubble-Eye Medaka
The Bubble-Eye Medaka grows to Up to about 4cm SL.
Temperature & humidity for the Bubble-Eye Medaka
The ideal temperature for the Bubble-Eye Medaka is 18〜28℃.
Basic Info
Origin
Japan (a trait discovered in 2008 by Mr Kubokouchi)
Lifespan
Care Specifications
- pH
- 7–8
- Hardness (GH)
- 9–19 dGH
- Water Temp.
- 18–28℃
PeacefulGroupBreeding: Hard
Sources: Medaka Web Encyclopedia: Complete Medaka Care Guide / FishBase Oryzias latipes / Medaka Web Encyclopedia: Bubble eye
Morphs (Varieties)
The Japan Medaka Association's classification manual sorts varieties by traits that can be seen rather than by genotype, and does not set out how individual traits are inherited. Traits the manual explicitly says can be passed on and produced by selective, multi-generation breeding are listed as line-bred; the rest are grouped under Other.
Other
Bubble eyeBig eye with bubble eye
Sources: Japan Medaka Association: Variety Classification Manual, 5th ed. (Sep 2025) / Medaka Web Encyclopedia: Medaka Traits / Medaka Web Encyclopedia: Bubble eye / Japan Medaka Association: List of Certified New Varieties
A curated selection of notable morphs. Inheritance modes are a breeding-planning guide; actual appearance varies with combos.
References & Sources
Edited & verified by: BreederDirect editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Primary sources
- Wikipedia
- CITES Appendices (species not listed)
- FishBase (IUCN Red List: Least Concern, assessed 2018)
- Medaka Web Encyclopedia: Complete Medaka Care Guide
- Medaka Web Encyclopedia: Bubble eye
- Japan Medaka Association: Variety Classification Manual, 5th ed. (Sep 2025)
- Medaka Web Encyclopedia: Medaka Traits
- Japan Medaka Association: List of Certified New Varieties
- FishBase
- GBIF
Taxonomy & Authority
Accepted name: Oryzias latipes (Temminck & Schlegel, 1846)
Breeder: (2008)
Authority databases: FishBase · GBIF · Medaka Web Encyclopedia: Bubble eye · Medaka Web Encyclopedia No.0671 (Blue big-eye bubble-eye)
Nomenclature follows global taxonomic authority databases.
Regulations & Conservation Status
Not CITES-listedIUCN LC · Least Concern
Sources: CITES Appendices (species not listed) / FishBase (IUCN Red List: Least Concern, assessed 2018)
Regulations may change. Always verify the latest information with the relevant authorities.
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